Christmas trees can be purchased as early as November, but it's recommended to purchase one closer to December, to ensure that it will last the entire holiday season. The best time to purchase a real Christmas tree is between Thanksgiving and Christmas Eve, when they are the freshest and most fragrant. Artificial trees can be purchased year-round, but they may not have the same scent or look as a real tree. When purchasing a real tree, make sure to get one that has been freshly cut, with needles that are green and don't fall off easily.